Patent GB-704670-A (GB)
Title: Improvements in and relating to automatic control of laundry washing machines and the like
Inventor: WOODWARD STANLEY
IPC: D06F33/02
Filed: 1950-09-06
Abstract: 704,670. Timed control of electric circuits. BAKER PERKINS, Ltd. Aug. 30, 1951 [Sept. 6, 1950], No. 21965/50. Class 118 (2). [Also in Group VIII] An automatic control for a machine or plant in which it is necessary to operate valves to deliver predetermined quantities of liquids at predetermined times comprises a rotary control card switch means to establish controlling circuits according to a predetermined formula, the drive for the control card being effected through a single one way drive means intermittently actuated by a solenoid or other suitable electrical means to which impulses are transmitted alternatively from make-and-break devices actuated respectively by a time motor and a meter or meters through which the liquid flows, means being provided for disestablishing the circuit inappropriate to the prevailing conditions. Fig. 2 is a schematic diagram of the invention applied to a laundry washing machine, all contacts being shown in their positions corresponding to the de-energized condition of the apparatus. A suitable low voltage supply is provided by mains 1 and 2. On depressing start button 3 the relay A is energized, closes holding contact A1 and starts the time motor G which is preferably a synchronous motor. Time motor G drives a make-and-break device G1 and thereby impulses solenoid T which operates a pawl and ratchet wheel as in Fig. 3 (not shown) to rotate step-by-step a drum 4 carrying the control card. The drum is provided with a gauze covering making contact with a common return finger 4b and the control card insulates fingers 5, 6, 7 from the gauze except where slots are provided in the card. When finger 5 is thus allowed to contact the drum relay B operates, opens contacts B1 and B3 and closes contacts B2 which operate relay C which holds over contacts C1 and also closes contacts C2. Finger 6 next encounters a slot in the control card and relay R is operated to open contacts R1 and stop the pulsator G1 driving the solenoid T. But contacts R3 energise a solenoid 15 which controls the flow of hot water to a washing machine, Fig. 1 (not shown), and a flow meter working a pulsator M1 takes over the drive of solenoid T since contacts R2 have now also closed. When drum 4 has rotated a predetermined amount finger 6 rides out of its slot in the card so that relay R and hence solenoid 15 are de-energized and the flow of hot water is stopped. Finger 7 now energises relay Q which by opening contacts Q1 prevents either G1 or M1 driving solenoid T but by closing contacts Q3 and Q2 energises a solenoid 21 controlling a main valve for the flow of various solutions to the washing machine and connects the associated flow meter pulsator M2 to drive solenoid T. Auxiliary fingers, Fig. 1 (not shown), on the drum 4 are used to operate valves to deliver predetermined quantities of various solutions, such as blue, soap, soda and meter flushing water, and then the control card interrupts the circuit of finger 7. Relay Q thus releases, disconnecting solenoid T from pulsator M2, closing the main valve by de-energization of solenoid 21 and reconnecting the time motor pulsator G1 to drive solenoid T. When the wash cycle is complete the control card interrupts the circuit to finger 5 thereby de-energizing relay B. Since relay C is holding, the closing of contacts B3 now energizes relay D which, at contacts D1, energizes relay E which holds over its contacts E1 and opens contacts E2. Contacts D2 open to disconnect the drive from pulsator G1 and contacts D3 connect solenoid T to the supply via contacts T1 which are trembler contacts carried by the pawl mechanism, Fig. 3 (not shown), such that the solenoid T operates rapidly to return the drum 4 to its initial or zero position, wherein the finger 5 again contacts the drum gauze and relay B is energized to open contacts Bl and de-energize relay A, which opens contacts A1 to disconnect the main supply from the apparatus. The drum 4 thus stops immediately the finger 5 enters the wash cycle slot in the control card and the apparatus is ready to commence a fresh cycle as soon as start button 3 is depressed. Should the power supply be interrupted during the final resetting part of the cycle the reset button 8 has to be depressed in addition to button 3 when the power is restored to bring about closure of contacts D3 and enable the reset movement to be completed. The pulsators G1, M1 and M2 comprise contact elements operated by cams driven by the time motor, water and solution meters respectively. The various relays energized by the fingers 5, 6, 7 ... and those controlling steam and dump valves on the washing machine are enclosed within a case which may be situated on the machine or located remotely. Specification 579,697, [Group VIII], is referred to.